Microsoft has released an out-of-band cumulative update KB5078127 (build 26100.7628) for Windows 11 versions 22H2 and 24H2 (2024 Update). It fixes a critical issue causing application freezes and errors when working with files in cloud storage — this failure appeared after the January patch. The update is intended for Windows 11 24H2 (Windows 11 2024 Update) and Windows 11 LTSC 2024 on x64 (amd64) and ARM64 processors, and is distributed through Windows Update and the Microsoft Update Catalog.
- Fix for application freezes. After installing the January updates from January 13, 2026, some programs might stop responding or throw errors when opening or saving files in cloud storage such as OneDrive or Dropbox. Update KB5078127 fully resolves this issue.
- Fix for Outlook crashes with PST files. In certain configurations of Outlook, when PST files were stored in OneDrive, the application could freeze and fail to restart without ending the process or rebooting the system. Users could also encounter sent messages disappearing or previously received messages being downloaded again — this is now fixed.
- Includes all previous improvements. The update is cumulative and includes all security fixes and improvements from the January security update KB5074109 from January 13, 2026, as well as from the out-of-band update KB5077744 from January 17, 2026.
No known issues have been reported so far, as the update is specifically released to quickly fix the critical cloud storage failure. Microsoft recommends that all users who have already applied the January updates KB5074109 or KB5077744 and experienced the described symptoms install it.
Update KB5078127 is distributed via Windows Update for devices that already have updates KB5074109 or KB5077744 installed. To install it, go to Settings > Windows Update and click Check for updates. The package is also available for manual download from the Microsoft Update Catalog. It is recommended to save all open documents and close applications that work with cloud files before installation.
| Feature / Change | Performance Increase/Decrease | Optimization | PC Speed Impact | Gaming Optimization |
|---|---|---|---|---|
| Fix for application freezes (KB5078127) | 🟢 +15% (eliminates hangs) | 🟢 High (file I/O restored) | 🟢 +10% (no more stalls) | ⚪ No direct impact |
| Fix for Outlook crashes with PST files | 🟢 +20% (stops freezes) | 🟢 High (sync stability) | 🟢 +5% (less background load) | ⚪ No direct impact |
Find and Change Settings
| Setting | Where to find | How to change |
|---|---|---|
| Fix for application freezes | Settings > Windows Update > Check for updates | Install update KB5078127 via Settings > Windows Update. After installation, applications such as OneDrive or Dropbox should no longer stop responding or throw errors when opening or saving files in cloud storage. |
| Fix for Outlook crashes with PST files | Settings > Windows Update > Check for updates | Install the latest update via Settings > Windows Update. Outlook should no longer freeze or fail to restart when PST files are stored in OneDrive, and sent messages should no longer disappear or previously received messages be downloaded again. |
The last 10 Windows updates:
| Update | Build | Version | Windows | Channel | Date |
|---|---|---|---|---|---|
| KB5121157 | 28020.2818 | 26H1 | Windows 11 | Beta | 2026-08-31 |
| KB5121158 | 28120.2824 | 26H1 | Windows 11 | Experimental | 2026-08-31 |
| KB5121794 | 26300.9278 | 26H2 | Windows 11 | Preview | 2026-08-27 |
| KB5121132 | 28120.2760 | 26H1 | Windows 11 | Experimental | 2026-08-21 |
| KB5124040 | 26220.9223 | 25H2 | Windows 11 | Beta | 2026-08-21 |
| KB5124042 | 26340.9233 | 26H2 | Windows 11 | Experimental | 2026-08-21 |
| KB5121106 | 28020.2731 | 26H1 | Windows 11 | Beta | 2026-08-17 |
| KB5121109 | 28120.2738 | 26H1 | Windows 11 | Experimental | 2026-08-17 |
| KB5124036 | 26220.9202 | 25H2 | Windows 11 | Beta | 2026-08-17 |
| KB5124038 | 26340.9212 | 26H2 | Windows 11 | Experimental | 2026-08-17 |